Changes to HTML5 & extensions sections
Changes to HTML5 & extensions sections

* Some reasoning/background to the HTML5 part
* Remove "(Adobe Flash, Microsoft Silverlight, OpenH264, Java ...)".
  This is not needed, as the details will follow and it resembles the
  old README's "highlights" part.

Toromtomtom/user.js,Toromtomtom/user.js,nodiscc/user.js,pyllyukko/user.js,pyllyukko/user.js,nodiscc/user.js